This is funny because the display of a fraternity’s letters on the nude breasts of an attractive female is used as an effective rush recruitment tool on many college campuses. Many sorority girls are reluctant to expose their breasts on camera, but the poster is implying that if her affection for the fraternity in question is sufficient enough, it can be exploited to convince her to agree to this request under the false pretext that it is for the greater good of the organization rather than his own personal satisfaction.

^This is funny because the original explanation contained a grammatical redundancy in the successive use of two synonyms. The subsequent reply pointed this out and then advised the original poster to “sit this next one out”, a common expression which refers to the practice in sports of a coach temporarily benching a player who has committed a significant mistake so that said player can reflect on their error and make mental adjustments to prevent it in the future. Although it originates in sports, this metaphor is frequently used as an insult on TFM to shame users who make jokes with poor wording or structure that fails to convey the intended humor properly.